let app = new VTTCue({
    el: '#app',
    data: {
        mas:"hello",
books: [
    {
        id: 1,
        name: '《算法导论》',
        data: '2006-9',
        price: 85.0,
        count: 1

    },
    {
        id: 2,
        name: '《UNIX编程艺术》',
        data: '2006-2',
        price: 59.0,
        count: 1

    },
    {
        id: 3,
        name: '《编程珠玑》',
        data: '2008-10',
        price: 39.0,
        count: 1

    },
    {
        id: 4,
        name: '《代码大全》',
        data: '2006-3',
        price: 128.0,
        count: 1

    }
]
},
    methods:{
        increase(index){
            this.books[index].count++
        },
        decrease(index){
            this.books[index].count--
        },
        remove(){
            this.books.splice(index,1)
        }
    },
    computed:{
        totalPrice(){
            let totalPrice = 0
            for (const item of this.books){
                totalPrice +=item.price * item.count
            }
        }
    }
})